Android 多线程的计数通信测试

代码：

package com.example.musicplayer;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.view.View;

import com.example.musicplayer.databinding.ActivityMainBinding;

public class MainActivity extends AppCompatActivity {
    private ActivityMainBinding binding;

    //工作线程的两种实现
    private Work work;
    private Work2 work2;

    //计数值
    private int num;
    private int num2=100;

    //判断是否计数
    private boolean ok;
    private boolean ok2;

    //用于多线程与UI线程之间通信
    private Handler handler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding=ActivityMainBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());
        initView();
    }

    private void initView(){
        work=new Work();
        work.start();

        work2=new Work2();
        new Thread(work2).start();

        handler=new Handler(Looper.getMainLooper()){
            @Override
            public void handleMessage(@NonNull Message msg) {
                //通过msg.what辨别通信对象，另外可通过msg.obj传递对象或字符串，msg.arg传递数字
                switch (msg.what){
                    case 100:
                        binding.textView.setText(num+"");
                        break;
                    case 200:
                        binding.textView2.setText(num2+"");
                        break;
                }
            }
        };

        //按钮点击控制计数
        binding.button.setonClickListener(new View.onClickListener() {
            @Override
            public void onClick(View v) {
                ok=!ok;
            }
        });
        binding.button2.setonClickListener(new View.onClickListener() {
            @Override
            public void onClick(View v) {
                ok2=!ok2;
            }
        });
    }

    //通过继承Thread实现
    private class Work extends Thread {
        @Override
        public void run() {
            while (true){
                while(ok) {
                    num++;
                    if (num > 100) num = 0;

                    try {
                        Message msg = Message.obtain();
                        msg.what = 100;
                        handler.sendMessage(msg);

                        Thread.sleep(100);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }

    //通过接口实现多线程
    private class Work2 implements Runnable{

        @Override
        public void run() {
            while (true){
                while(ok2) {
                    num2--;
                    if (num2==0) num2=100;

                    try {
                        Message msg = Message.obtain();
                        msg.what = 200;
                        handler.sendMessage(msg);

                        Thread.sleep(500);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }
}